Scientists have succeeded in reactivating 27,000- to 48,500-year-old viruses found in permafrost, the frozen underground soil whose temperature remains below 0°C for more than two consecutive years.
In some regions, such as Siberia, the thickness can reach several hundred meters. These icy expanses make up 90% of Greenland, 80% of Alaska, 50% of Russia, and altogether make up one fifth of the earth’s surface.
However, with global warming, the melting of permafrost is accelerating, releasing large amounts of greenhouse gases and numerous microorganisms, viruses and bacteria that have been trapped in the ice until now.
In a study published on the scientific pre-publication server of Biology bioRxiv, researchers from the University of Aix-Marseille explain how they reanimated several viruses collected in Siberian permafrost. The oldest, 48,500-year-old pandoravirus, is still alive and able to reproduce.
Working on the subject for ten years, the group isolated thirteen viruses from seven samples, one of which was taken from the Lena, one of the world’s longest rivers.
Already in 2014, these scientists succeeded in reviving a virus from 30,000 years ago. Today, thanks to genome sequencing techniques, five types of giant viruses have been identified, the oldest of which, at 48,500 years old, almost reaches the limit of possible carbon-14 dating.
These dormant viruses in the Siberian permafrost do not pose a direct threat to humans, but other viruses that have been buried for millennia can reactivate and become dangerous. The coordinator of this study, Jean-Michel Clavery, professor emeritus of public health universities and virologist at the University of Aix-Marseille, sheds light on the reality of this threat.
How did you and your French, German and Russian colleagues manage to resuscitate these viruses, the oldest of which is 48,500 years old?
The oldest (carbon 14) comes from a permafrost layer up to 48,500 years old. It is important to understand that viruses can live for more than 50,000 years. However, with carbon 14 dating technology, we are limited to this date. To go further, we will need to use methods that are not available to us. Only seven viruses come from old, well-dated permafrost layers. Others are either modern or from a mixture of different layers of melted permafrost.
Should we be worried about these viruses spreading as a result of global warming and melting permafrost?
With global warming, the spread of viruses is accelerating, and we are witnessing the “industrial colonization” of the Arctic, which increases their chances of encountering and infecting human hosts. But the viruses we reanimate and study do not pose any danger to humans. We only work on specific amoeba viruses. However, they serve us as an indication that if amoeba viruses can remain infectious for so long, there is no reason why older and unknown viruses capable of infecting animals and humans should not be equally infectious. , are preserved as inert particles. seed.
The Russians have announced plans to resurrect the mammoth viruses we consider unnecessarily risky…
By studying the total DNA of permafrost, we identify these viruses by their metagenomic sequencing (a method of studying the genetic makeup of samples from complex environments taken from nature – Editor’s note), but we do not awaken them. Conversely, the Russians have announced plans to resurrect mammoth viruses, which we consider to be unnecessarily risky…
What about bacteria in permafrost? What would happen if they were released?
The bacteria are less dangerous because they will be sensitive to current antibiotic treatments. Not viruses. Each new virus requires specific responses: no vaccine for AIDS, only drugs, no drugs for Covid, only vaccines, more or less effective…
Will current antibiotics help protect us?
Bacteria yes, not viruses…
What will be your next research?
Now we turn to Antarctica. I will soon be going to Italy to look for specimens brought in by an oceanographic boat Laura Bassey) of the expedition ending in 2022. Our interest is primarily fundamental: exploring the diversity of amoeba viruses, but their awakening is relevant to our “applied” research to assess public health risks from thawing permafrost.